Process of making n-vinyl morpholine



PRQCESS (BF MAKING N- INYL MORPHOLINE Norman Blumenlropt', North Merrick, N.Y., and Otto F.

Hecht, Easton, Pa, assignors to General Aniline ii: Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 7, 1959, Ser. No. 844,870 3 Claims. (Cl. 260-247) This invention relates to the preparation of new and useful compounds, and in particular, to the preparation of N-vinyl morpholine and vinylated derivatives of substituted morpholines.

While enumerable vinylated compounds are known, and among this tremendous group some vinylated amines containing the vinyl group directly attached to the nitrogen atom of the amine, N-vinyl compounds of amines in general are extremely difficult to come by. It has been well recognized in this art that the vinylation of primary and secondary aliphatic amines does not result in any useable or readily obtainable vinylated product. In such reactions the result is usually a tarry mixture. Success has been achieved where the vinylation has been attempted on low basicity secondary amines, the outstanding example being N-vinyl carbazole. It has generally been accepted that the direct vinylation with acetylene of basic amines is not a feasible method for the preparation of such compounds, and that only those amines which exhibit acidic properties could be employed in such a reaction.

Contrary to all expectations, however, it has been found that morpholine, a highly basic compound, and numerous derivatives of morpholine, can be vinylated directly with acetylene to give the N-vinyl compounds.

It is therefore an object of the present invention to provide a process for the preparation of N-vinyl morpholine and derivatives thereof.

Other objects will appear hereinafter as the description proceeds.

The compounds proposed by this invention are the N-vinyl derivatives of morpholine and'the alkyl, alkoxy, aryl and other inert derivatives of morpholine.

In addition to morpholine itself, the following derivatives thereof within the scope of the above described class of derivatives may be employed:

Z-methyl morpholine 2-ethyl morpholine 3-ethyl morpholine 2-ethoxy morpholine 2-phenyl morpholine 2(3,4-dioxy phenyl) morpholine 2,6-dimethyl morpholine 2,3-dimethyl morpholine 2,6-diphenyl morpholine 2,5-dimethyl morpholine 3,5-dimethyl morpholine" 2,6-diethyl morpholine Z-ethyI-S-methyl morpholine 2-methyl-5-ethyl morpholine 2,6-ditertiary butyl morpholine 3-methyl-2-phenyl morpholine, and the like.

Among the various substituents above enumerated in the morpholine nucleus, it is preferred that the alkyl and United States Patent e attassi Patented Apr. 20, 1965 alkoxy substituents be of the lower alkyl or lower alkoxy type of from 1 to 6 carbon atoms, and encompassing thusly methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, amyl, and hexyl. Of the aryl substituents it is preferred to employ the monocyclic, carbocyclic types such as phenyl and derivatives of phenyl such as tolyl, xylyl, halophenyl, alkoxy phenyl and the like.

The preferred method for the preparation of the compounds of this invention involves the interaction of the selected morpholine or derivatives thereof with acetylene. The reaction is usually conducted in a stirred autoclave at a temperature of from about 50 C. to 180 C. Elevated pressures may be employed derived from the use of superatmospheric pressures of acetylene and mixtures of acetylene with inert gases such as nitrogen and the like. However, elevated pressures are not necessary due to the unexpected and extreme ease of reaction of acetylene with morpholine and the morpholine derivatives described above. The preferred temperature of operation is from about C. to 120 C. and within this range a temperature of C. has been found to give the best results. The selected morpholine may be vinylated without dilution although it is preferred to employ an inert solvent such as benzene, toluene, xylene, cyclohexane and other hydroaromatic solvents, and the like. From about 1 to 50% morpholine by weight based on weight of solution may advantageously be used. A 10% to 50% solution is preferred.

To eifect the reaction it is necessary that a catalyst be employed. The preferred catalyst is an organic cadmium salt such as anhydrous cadmium acetate, cadmium stearate or cadmium naphthenate. Zinc salts are also suitable. The amount of catalyst employed is not critical and may Vary from about 0.1 to about 10% by weight calculated as metal based on the weight of the morpholine compound. Due to the extreme reactivity of the N-vinyl morpholine monomers, it has been found desirable, in order toobtain maximum monomer yields, to employ during the vinylation reaction, an inhibitor. Phenyl-Z- naphthylamine and substituted aminoanthraquinones have been found outstanding for this purpose. Among the aminoanthraquinones which are suitable are the following: it

1,4-bis(methylamino) anthraquinone 1,4-bis acetylarnino) anthraquinone 1,4-bis(propio11ylamino) anthraquinone 1,4-bis (methylamino -5, S-dihydroxy anthraquinone 1,4-bis (ethylamino) -5 8-dihydroxy anthraquinone l-butylamino-4-methylamino anthraquinone The amount of the above described compounds which can be employed as inhibitors in the practice of this invention will vary considerably and is in no way critical. It has however, been found that amounts from about 0.001% up to about 2% thereof based on the weight of the monomer. provide adequate protection to the monomer whereby polymerization is inhibited under the conditions hereinafter to be described. From 0.01% to about 1% is preferred.

The N-vinyl morphoiines as described above are extremely active monomeric compounds and polymerize very rapidly upon exposure to air at room temperatures to yield substantially colorless to yellowish, transparent,

polymers.

out being deemed limitative thereof. .weight unless stated otherwise.

7 3 oily orflexible polymers. In addition, the monomers of this invention may be copolymerized with numerous other ethylenically unsaturated compounds to yield copolymers and interpolymers of great variations in prop erties. The N-vinyl morpholine polymers and copolymers may be prepared in any one of a number of different structural forms such as sheets, films, coatings, fibers, filamerits, molding powders and the like. Because of the somewhat basic nature of the polymers produced in accordance with this invention, they are admirably suited for dyeing with a great variety of different types of dyestuffs. Dyes which are normally used for the dyeing of wool and nylon give outstanding results with such polymers. Dispersed dyes of the iazo and anthraquinone series also may be employed to effect dyeings of these By virtue of the outstanding affinity of these polymers for the large variety of the above enumerated dyestuffs, it is possible to modify other polymer materials to increase the dye affinity thereof for similar dyestuffs. Thus a copolymer of acrylonitrile and N-vinyl morpholine containing N-vinyl morpholine is readily dyeable whereas in the absence of the N-vinyl morpholine constituent, dyeings are obtained with great difficulty. Not only may the N-vinyl morpholines be used as components of ooipolymers and interpolymers, but they may also be used to modify the properties of other polymers in admixture therewith. It is also possible to treat numerous polymeric materials with the monomers of this invention and polymerize said monomers in situ whereby distinct copolymers, interpolymers, graft polymers, and/ or mixtures of polymers are produced. The following examples will serve to illustrate the present invention with- All parts are by Example 1 174 parts (2 mols) of freshly distilled morpholine are mixed with 174 parts of benzene, then 2 parts (1.1 of the weight of the morpholine) of phenyl-Z-naphthylamine are dissolved in the mixture, and finally there are added 4 parts anhydrous cadmium acetate (con'esponding to 2 parts cadmium metal or 1.1%, based on the weight of "the morpholine).

This mixture is now placed in a stirred one-liter autoclave of stainless steel, which is purged three times with nitrogen for removal of oxygen prior to the reaction. Then a mixture of equal parts by volume of nitrogen and acetylene is introduced up to a total pressure of 120 p.s.i.g. The temperature of the autoclave is then raised to 100 C., where reactive absorption of the acetylene takes place. Then the total pressure is now brought up to 200 p.s.i.g. with pure acetylene. The consumed acetylene is replenished every half hour by introduction of fresh acetylene up to 200 psig. total pressure. The absorption is rapid and the reaction is stopped when about 95% of the theoretical acetylene absorption (50 parts by weight [=1.93 moles], corresponding to a cumulative pressure drop of about 900 p.s.i.), is reached, which re quires about hours.

After cooling, the clear, brownish solution is then distilled under a vacuum of mm. of mercury to remove the benzene solvent. The residue is then fractionally distilled at 3 mm. to give a product which boils at this pressure at 19 C. The resulting product has a refractive .index N =1.4775 and analyzes as N-vinyl morpholine.

The yield of monomer based on the amount of morpholine consumed is 65%. The monomer is distilled into a receiver, cooled in a mixture of Dry Ice and acetone to -80 C. A small amount of a white crystalline product separates. This product is a water soluble material having a melting point of 105 C. and a sublimation temperature of C. The infra-red spectrum of this product indicates the product has the following formula:

N-CHCH3 and is formed by reaction of 1 mole morpholine with 1 mole N-vinyl morpholine. -After separation of this solid. crystalline precipitate, the remaining monomer is then Example 2 The procedure of Example 1 is repeated employing 1 part of anhydrous cadmium catalyst. A yield of 56% N-vinyl morpholine is obtained.

Example 3 The procedure of Example 1 is again repeated employing 1 part of anhydrous cadmium succinate as a catalyst. A yield of 60% vinyl morpholine is obtained.

Example 4 Example l is again repeated using 1 part of cadmium stearate (anhydrous) as the catalyst.- A yield of 46% N-vi-nyl morpholine is obtained.

Examples 5-10 In the following examples, Example 1 is repeated employing the recited morpholine derivatives in 'lieu of morpholine in Example 1:

Yield, percent xample Compound Example 11 Example 1 is again repeated employing a 50% solution of morpholine in cyclohexane and as the catalyst, Zinc naphthanate in an amount sufficient to yield 2% metal based on the weight of the morpholine. The yield of monomer obtained is 45%.

Example 12 Example 11 is repeated employing, however, as the polymerization inhibitor, 1,4-bis(methylamino) anthraquinone. A 48% yield of monomer is obtained.

Example 13 Example 1 is once again repeated employing, however, a temperature of vinylation of C. The yield of mon omer obtained is about 25%.

Other variations in and modifications of the described processes which will be obvious to those skilled in the art can be made in this invention without departing from the scope or spirit thereof.

We claim:

1. A method for the preparation of N-vinyl morpholine which comprises reacting morpholine with acetylene at a temperature of from about 50 C. to about C. in the presence of a polymerization inhibitor and anhydrous cadmium acetate as a vinylation catalyst.

2. A method for the preparation of N-vinyl morpholine which comprises reacting morpholine with acetylene at a temperature of about 100 C. in the presence of a polymerization inhibiting amount of a compound selected from the group consisting of phenyl-Z-naphthylamine and substituted-amino anthraquinone and about 1 to 3% by Weight calculated as free metal of anhydrous cadmium acetate as a vinylation catalyst.

3. A method for the preparation of N vinyl morpholine which comprises reacting a solution of morpholine in an inert organic solvent with acetylene at a temperature of about 100 C. in the presence of from about 0.01% to about 1% of a compound selected from the group consisting of phenyl-Z-naphthylamine and substituted-amino anthraquinone polymerization inhibitor and from about 0.1% to about 10% by Weight calculated as metal based on the weight of the morpholine of anhydrous cadmium acetate as a vinylation catalyst.

G5 References fitted in the file of this patent UNITED STATES PATENTS 2,618,020 Busse et a1. Nov. 18, 1952 2,664,378 Heller Dec. 29, 1953 2,806,848 Nedwick Sept. 17, 1957 2,891,058 Walles et a1. June 16, 1959 2,984,656 Lal lay 16, 1961 2,989,496 Palm et al June 20, 1961 FOREEGN PATENTS 940,981 Germany Mar. 26, 1956 OTHER REFERENCES Reppe et al.: Justus Liebigs Annalen der Chemie, vol. 601, pages 128132 (1956).

Raphael: Acetylenic Compounds in Organic Synthesis :(textbooli) (1955), page 39; Academic Press Inc.,

London. 

1. A METHOD FOR THE PREPARATION OF N-VINYL MORPHOLINE WHICH COMPRISES REACTING MORPHOLINE WITH ACETYLENE AT A TEMPERATURE OF FROM ABOUT 50*C. TO ABOUT 180*C. IN THE PRESENT OF A POLYMERIZATION INHIBITOR AND ANHYDROUS CADMIUM ACETATE AS A VINYLATION CATALYST. 